Perpendicular magnetic recording head and perpendicular magnetic recording apparatus

Abstract

A perpendicular magnetic recording apparatus includes a magnetic disk having a perpendicular double-layer film and a perpendicular magnetic recording head having a leading pole positioned forward along the head traveling direction, a trailing pole positioned backward along the head traveling direction at a gap length from the leading pole and having, in an air-bearing surface, a forward pole and a rearward pole of which saturation magnetic flux density is higher than that of the forward pole, and an exciting coil. A length p of the trailing pole along the head traveling direction is longer than a length T of the trailing pole in a track width direction, the length p is longer than the gap length g 1 , and a length p 1 of the rearward pole is shorter than a length p 2 of the forward pole along the head traveling direction.

What is claimed is:  
     
       1. A perpendicular magnetic recording head comprising: 
       a leading pole positioned forward along a head traveling direction;  
       a trailing pole positioned backward along the head traveling direction at a gap length g 1  from the leading pole, the trailing pole having a length p along the head traveling direction and a length T in a track width direction, and the trailing pole comprising, in an air-bearing surface, a forward pole having a length p 2  along the head traveling direction and a rearward pole having a length p 1  along the head traveling direction of which saturation magnetic flux density is higher than that of the forward pole; and  
       an exciting coil,  
       wherein the length p of the trailing pole along the head traveling direction is longer than the length T of the trailing pole in the track width direction, the length p is longer than the gap length g 1  between the leading pole and the trailing pole, and the length p 1  of the rearward pole along the head traveling direction is shorter than the length p 2  of the forward pole along the head traveling direction.  
     
     
       2. The head according to  claim 1 , wherein the length p 1  of the rearward pole along the head traveling direction is shorter than the length T of the rearward pole in the track width direction. 
     
     
       3. The head according to  claim 1 , wherein an air-bearing surface of the forward pole is recessed from the air-bearing surface of the rearward pole. 
     
     
       4. The head according to  claim 1 , wherein the leading pole is used as one of a pair of shields sandwiching a reproduce element. 
     
     
       5. A perpendicular magnetic recording apparatus comprising: 
       a magnetic disk comprising a perpendicular double-layer film of a soft magnetic backing layer and a perpendicular magnetic recording layer; and  
       a perpendicular magnetic recording head comprising a leading pole positioned forward along a head traveling direction, a trailing pole positioned backward along the head traveling direction at a gap length g 1  from the leading pole, the trailing pole having a length p along the head traveling direction and a length T in a track width direction, and the trailing pole comprising, in an air-bearing surface, a forward pole having a length p 2  along the head traveling direction and a rearward pole having a length p 1  along the head traveling direction of which saturation magnetic flux density is higher than that of the forward pole, and an exciting coil,  
       wherein the length p of the trailing pole along the head traveling direction is longer than the length T of the trailing pole in the track width direction, the length p is longer than the gap length g 1  between the leading pole and the trailing pole, and the length p 1  of the rearward pole along the head traveling direction is shorter than the length p 2  of the forward pole along the head traveling direction.  
     
     
       6. The apparatus according to  claim 5 , wherein the length p 1  of the rearward pole along the head traveling direction is shorter than the length T of the rearward pole in the track width direction. 
     
     
       7. The apparatus according to  claim 5 , wherein an air-bearing surface of the forward pole is recessed from the air-bearing surface of the rearward pole. 
     
     
       8. The apparatus according to  claim 5 , wherein the gap length g 1  between the leading pole and the trailing pole, a distance d between an air-bearing surface of the trailing pole and an upper surface of the magnetic disk, and a distance s between the air-bearing surface of the trailing pole and the upper surface of the soft magnetic backing layer of the magnetic disk satisfy a relationship of d<g 1 < 2   s.    
     
     
       9. The apparatus according to  claim 5 , wherein a gap length g 2  between the leading pole and the rearward pole of the trailing pole, and a distance s between an air-bearing surface of the trailing pole and an upper surface of the soft magnetic backing layer of the magnetic disk satisfy a relationship of  2   s <g 2 < 20   s.    
     
     
       10. The apparatus according to  claim 5 , wherein the leading pole is used as one of a pair of shields sandwiching a reproduce elements.